Conveyer belt



Jan. 31, 1939.

P] J BIRKMEYER CONVEYER BELT Fil ed March 5, 1936 4 L/ih FIG. 3

FIG. 2

INVENTOR P. J. BIRKMEYER FIG. I

M 6m AT RNEY j fi UNlTED "ST "Patented Jan-3 PATENT OFFICE CONVEYER BELT Paul J. Birkmeyer, Verona, J., assignor to The Western Union Telegraph Company, New York, N. Y., a corporation of New York Application March ,5, 1936, Serial No. 67,389 "16 Claims. (01. 198-165) This invention relates to belt conveyers in which sheet material is carriedbetweentwo fiat I I belts, and has particular reference to an improved type of conveyer belt. t

.5 I Conveyer belts are quite extensively used for conveying sheet material, telegram blanks,'messages, and the like, from one part of abuilding to another. -Forcertain purposes, and under certain conditions, a double or multiple strap con.-

veyer, with which type the present invention is johiefiy associated, has been found to be most 'suitably adapted. ,Such a conveyer is highlydesirable, for use in carrying light, flexible sheet material for inter-.oflice communication, and'is often, necessary where for some reason it is im- 'practical to install the well known drag type of 'conveyer in which the sheet material is carried between ,a stationary guide member and a belt by frictional engagement with the latter.

The double strap conveyer comprises two parallelbelts traveling in the same direction with their inner faoes inengagement with each other.

type of conveyer is ordinarily supported by means ofthe direction changing rollers and other 5 suitable guide fn embers conveniently spaced therebetween, It has been found that whenever,

- the conveyer must .spana relativelyv wide gap without the cooperation of any support member, forvthe belts, there is a tendency. for the belts to separate, thus allowing the message to fall-out. I In addition to' this difficulty there has been'noted a tendency for onebelt or strap to creep over theother' when-they are both passing around the same direction changing pulley.

V5 ,To counteract" thetendency of the belts to separatef or slip, and to, increase the gripping action of one belt upon the other, it is sometimes customary to, give the belts one or'moretwists be. tween rollers wherever the gap is wide enough to 4 permit the same. Any number of twists may be "given the belts, limited somewhat, of course, ,by V therigidity of the belt material and by the thickness or Widthv of the belt. I i One of the chief difficulties encountered in twisting a conveyerbelt in the past has been the tendency for the edges to curl or fold towardfits longitudinal center. This is due to a large extent to the fact that as the belt istwisted, a point on its outer edge travels a helical, and hence a longer, path than a, point at the center, thus causing the longitudinalbelt fibres or strands to be proportionately elongated or stretched according to their lateral distance from the center. The tendency of the stretched portion to seek the s i'shortest path, or the one oi least resistance, sometimes causes the outer edges of the belt to curl sult that the outer edges of the belt become wavy or non-planiform in shape and the effective gripping surface of the belt is materially decreased. Hence, one of the objects of this invention is I to provide a belt material having a relatively nonelastic longitudinal central portion and elastic outer portions so that when the outer portions of the belt are stretched and released, they will reassume their normal shape.

- Another object is to provide a belt material which is reinforced transversely so as to be relatively non-flexible or resistantto curling from the edges toward the center.

Still another object is to provide a conveyer belt which, when used with a double strap twist conveyer, will not permit the sheet material to wrap around, the belt as it is. twirled around in its travel through the twisted portion 'of the conveyer.

A further object is to provide a woven fabric belt material in which the transverse fibres or strands are non-elastic and equi-spaced and in which the longitudinal strands are non-elastic at the center portion of the belt and increasingly elastic toward the edges.

Another object is to provide a woven fabric belt material having the central strands of the warp tightly woven and the outer strands loosely woven and having a uniform weft.

These and other objects of my invention will be apparent from the following description and claims taken in connection with the accompanying drawing in which:

Fig. 1 is a fragmentary top view of a portion of 'belt, material composed of two separate layers of difierent widths suitably joined together; Fig. 2 is anend view of two such belts, as shown in Fig. 1, arranged in conveying relation;

Fig. 3 is a modified form .of the belt material shown. in Fig. 2 in which a series of reinforcing strips are inserted in the weave of the belt;

Fig. 4 shows a fragmentary portion of belt material having a varied weave from the central Fig. 8 is a modified form of belt pulley;

Fig. 9 shows a fragmentary portion of varied.- weave belting in which the warp and weft are uniform as to spacing but vary as to the tension on certain strands;

Fig. 10 is an enlarged cross-section View take along the line Ill-l of Fig. 9;

Fig. 11 is an enlarged section view taken along the line-ll-ll of Fig. 9; and

Fig. 12 is an enlarged view taken along l2--l2 of Fig. 9. I

Referring now to the drawing, Fig. 1 showsa fragmentary view of a length of belt material composed of two layers joined one above the other. paratively non-elastic belting [2 consisting of rubberized fabric, tightly woven duck o-r' canvas,

or similar material, is laterally centered on; andafiixed longitudinally along, the entire length of a. substantially wider and thinner piece of fabric belting l3, the;latter. having a substantially stiffweft and a substantially flexible and elasticwarp. There is thus formeda belt having a double or reinforced center portion and overhanging side portions. The outer surface. of the Wide layer forms the sheet engaging or conveying surface of the belt. The two layers are permanently joined together by any suitable means, as by stitching or, clipping.

With this type of belting it is possible to stretch the material at the outer edge while the center portion. of the belt remains substantially unchanged. This is particularly desirable where the belt is given one or more twists, thus causing the outer edges of the belt to be subjected to more tension than thecenter portion. This construction also permits the belt material to reassume its normal shape after having'been stretched and distorted in. operation; A

Fig.2, shows a sectionalend view of a. double strap arrangement comprising two belts, as shown inFig. 1, arrangedin conveying relation. It will be noted that the outer face or working surface of the elastic portion. 13 of each belt adjoins or faces the corresponding surface of the other. belt.

Fig. 3 shows a modified arrangement of the belt material shown in Figs. 1 and 2, with the additional feature of havingthe lower or wide.

belt layer I3 reinforcedtransverselyby splints or strips. l 4 inserted between the strands or fibres of the woven fabric and spaced at equal intervals along the entire length of. the belt. The splints 14 are constructed of materialof less flexibility than the. fabric inwhich they are insertedand extend the entire width of the belt so ,as to rein.- force the same and prevent the latter from curling transversely toward the center. As the belt is twisted in spiral fashion, these splints I4 serve.- V to maintain the belt in a manner to causea transverse element at any point along the conveyer path to be in a substantially straight line.

Fig. 4 shows a section of varied-weave conveyer belt material l5. comprising a single layer or flat strip of woven fabric. is. constructed so that the center portion 16 com.-

.prising about one-half of the total width of the belt will have a very close weave and sturdy construction with the longitudinal strands being sub,- stantially on-resilient and equi-spaced. From the center. portion Hi to the outer edges, the

longitudinal strands of the marginal portions IT! A length of heavy closely woven,.and com- The belt material.

are gradually varied as to both spacing and re siliency, so that the outer edges of the belt have a relatively high degree of resiliency. Throughout the entire length of the belt fabric the transverse strands are uniformly spaced and tensioned and are of a strong, non-resilient material.' Whenever the belt is subjected to a series of twists, and operated under conditions tendingto causecertain longitudinal strands to be stretched more than others, this construction serves to pre- It also permits the use of a wider belt'than has heretofore been practical for use in twist conveyers because the outer portions of the belt may expand or contract as necessary under varying conditions of operation.

Fig. shows an end view of'two such varied weave belts in conveying arrangement. It will be observed from the drawing that the beltmaterial is of even'thickness across its entire widthgreatest dispatchpossible, thus introducing the factorof air resistance. While a thin sheet traveling edge foremost is not appreciably affected eration, it is desirable to have the sheet material transported from one place to another with the by air resistance, a sheet traveling along a twist conveyer and having its plane revolved in spiral the. conveyer belts.

Referring to the figure, I have shown. a double high frictional characteristic, extending long-i tudinally along the entire length of the belt so that it may-exert a strong gripping action on the sheet material coming in contact therewith.

It will be noted from the figure that when two such belts are arranged with their working 7 surfaces contacting each other, and with the belt portions l9 in vertical alinement, the overlapping belt portions are oppositely projecting. The belt conveyer is twisted in the direction 'indicated so that the overlapping portions will follow and urge around in spiral fashion the projecting portions of sheet material, such'as T, inserted between the belts. With this arrangement the belts may be constructed wide enough so that the portions of the projecting sheet material that are subjected to the air pressure as they revolve will'be provided with'a backing so that they will-be prevented from curling about the belt. Inv addition, the air pressure will forcethe action of the belt. 4 r

caused to'curl under the belt" so that the same will" not catch against and be mutilated by the ed on a shaft'25. The

pulley, or be folded under the belt as it''passes over and around the pulley. A double strap conveyer 22 with a message blank T inserted therebetween is shown passing over a pulley 24 mountbelt engaging portion 26 slightly crowned I or tapered' up toward the center and of awidth substantially equal-to that of the belts. The pulley is cylindrically ektended at both sides- 21 and 28 to engage and lift the curled edges of the sheet material as it passes over the roller. 1

1 :Fig. 8 shows another modified formof beltpulley' 'designed to accomplish the same purpose but having the extended portions of thepulley taper- I ing'toward the'shaft as at '29 and. 30..

-Fig. 9'shows a modified form of varied-weave belting in which the strands of the warp and weft aresubstantially 'equi-spaced, but wherein the tension of certain strands is varied to produce a fabric having zones of varying resiliency. The longitudinal strands at the central portion 32 of I the belt 3l. are drawn tightly so'that the resil- I resiliency of the central portion. Theouter poriency of the belta's a whole will belim'ited by I tions 33 of the belt are constructedwith the longitudinal strands loosely woven'so that they may readily be stretched. The effect of this variation i is shown more clearly in Figs. 10, and 11.

Fig..10;is an enlarged view of a section of fab .ric belting wherein the warp comprises loosely woven strands. It will be noted that the warp thread 34 takes a pronounced undulatory course as it passes over and under the weft threads 35.

, Thislooseness permits theadjacent weft threads to be substantially offset from the mean center I line.- With this construction the thread 35 may foobe easily stretched.

' Fig. 11 shows the effect of drawing the warp thread 34 tightly through the. weft. Here it will 7 I 'be observed that the warp has been made to fol- 'low the shortest possible In this case the weft threads 35 are all in a substantially straight line. Itis thus apparent that the variation in resilient properties between a section of belting having a loose weave and asection' having tightly woven strands is caused by theability of the strands to changetheir con- Fig. 12 shows an enlarged sectional view of the A portion of thetightly woven center in a substantially straight line. Atpthe outer portion 33 theloose warp strands are slightly offset from the center line and hence the warp thread 35 will have a path substantially as shown.

As with the varied-weave belting in which the spacing of the strands is non-uniform, this type of belt fabric permits the outer edge portions to be stretched independently of thecentral pertion.

From the foregoing description it will be ob -p I served that I have provided a novel belt construe tion that is especially desirable for use with twist .conveyers or any type of conveyer wherein the "outer'portions of the belt are subjected to a great- Fig. 7 shows a modified form of belt pulley designed to straightenoutmessages that have been pulley comprises a main path through the .weft/ er' strain than the central portion, and wherein and a substantially uniform and non-resilient weft.

1 2. A fabric conveyer belt material comprising a non-uniformly spaced warp, said warp being closely spaced at the center and increasingly spaced toward the outer edges, and a weft having a substantially uniform spacing.

3. A woven fabric conveyer belt material comprising a non-uniform warp, the central strands of which are close together and the outer strands of which are further spaced and more resilient, and a uniform weft having strands which are relatively non-resilient and uniformly spaced.

4. A fabric conveyer belt comprising a warp having closely adjacent strands at the center portion and wider spaced and more resilient strands toward the outer edges, and a weft having uniformly spaced substantially non-resilient strands, whereby said outer portions of the belt may be stretched independently of said center portion.

5. A fabric conveyer belt comprising a warp having closely adjacent strands at the center portion and spaced wider and more resilient strands at the outer portions, and a weft having uniformly spaced substantially non-resilient strands, said belt having a uniform thickness throughout.

6. A conveyer belt comprising two layers, one of said layers being composed of a strong relatively non-resilient material and the other layer being substantially wider than said first layer and composed of a more resilient material, said second layer being aifixed to said first layer so that only the overhanging portions of said second layer may be materially stretched.

7. A conveyer belt comprising a resilient belt member, a second belt member of less resilient I I along the center of one face, the opposite face of said first member providing the working or engaging surface of said belt.

8. A fabric conveyer belt composed of two layers the first or lower layer comprising a thin resilient fabric, and the upper or second layer comprising a heavy non-elastic material, said upper layer being substantially narrower than said lower layer and'aflixed longitudinally along the center thereof to provide equal overhanging portions whereby said narrow belt layer prevents stretching of the belt as a whole while the resiliency of the overhanging portions of the wide layer permits elongation of the outer portions whenever said belt is twisted.

9. A conveyer belt as disclosed in claim 8 and having inserted in the weft of said lower fabric layer a plurality of stiffening members whereby said layer is rendered resistant to transverse bending.

10. A conveyer belt as disclosed in claim 8 and being provided with a plurality of transverse splint members extending the entire width of the belt and affixed to the lower layer, said splints being being relatively non-flexible and spaced therealong at intervals to restrain transverse fiexion of said, belt. v

11. A conveyer belt comprising a main belt member of sturdy and substantially non-resilient construction, a second and substantially wider belt member of resilient construction affixed to the-lower face of said first belt member andjhaving the overhanging portion projecting from one side of said first beltmember, and a raised strip portion projecting from the lower face of said second belt member and extending longitudinall along the overhanging edge thereof. a

12. In a belt-conveyer system a double strap belt arranged to carry sheet material therebetween, supports for said belt, one or more twists in said belt between said supports, saidbelt comprising a broad, resilient belt member having affixed to one side of its upper surface a substantially narrower belt member, said member being non-resilient and of relatively sturdy construction, and a substantially'narrow raised strip ex- 7 tending longitudinally along and projecting downwardly from the lower face of said broad belt member at the opposite side thereof, whereby, when two such belts are disposed in double strap arrangement with the lower faces contacting each other, theoverhanging portions will be oppositely projecting so that sheet material inserted between said belts will have their opposite faces contacted by the narrow strip members.

13. A belt conveyer system for conveyingand maintaining message blanks in an unfolded condition comprising a pair of belts, each of said belts having a marginal portionrelatively elastic in' a longitudinal direction and being relatively inelastic longitudinally adjacent said marginal portion, pulleys for supporting said belts, said belts being twisted between said pulleys, and causing said marginal portions to travel a longer, path than that taken by said inelastic adjacent portion, the relative elasticity of said marginal por-' tion preventing lateral curling of the belt.

14. The conveyer system of claim l3 wherein each of said belts is provided with a. relatively narrow raised strip projecting from the surface which is in contact with the other belt whereby said blanks inserted between the belts will have their face or faces contacted by the narrow strip members. V

15. A conveyer belt for a double belt conveyer system in which a pair of twisted contacting belts are employed to carry blanks flatwise, said belt comprising a longitudinally elastic marginal portion and a 'less elastic portion adjacent said marginal portion whereby to prevent said belt from-doubling upon itself in use.

16. A conveyer beltfor a double belt-conveyer system in which a pair of twisted contacting belts are employed to. carry blanks fiatwise, said belt comprising longitudinally elastic marginal por-j tions and a less elastic portion extending longitudinally of said belt between said elastic portions. f

PAUL J. BIRKMEYEBGL 

